In the course of the production of such products, it is necessary to measure for the purpose of an inspection or a regulation, characteristics which are difficult to measure in a continuous manner. This is in particular the case of characteristics such as the flatness or the yield strength for example. Usually, for the purpose of measuring these characteristics, a person skilled in the art has to take samples from the product and effect measurements which are remote from the production line and are therefore differred measurements. This manner of proceding presents several drawbacks among which are:
it is necessary to take a sample and therefore to cut off this sample, which may interrupt the continuous character of the production;
it is impossible to achieve a continuous regulation.